Records from the New York's Emigrant Savings Bank show that nearly 40 percent of Irish immigrants were able to save the equivalent of $10,000 in today's money, often in a decade or less.

Tyler Anbinder’s article "Moving beyond “Rags to Riches”: New York's Irish Famine Immigrants and Their Surprising Savings Accounts" argues that immigrants that fled the famine in the mid-1800s were not a "floating proletariat.”

He argues that some historians have misunderstood immigrant success, as they focused on factors like occupational status and home ownership.

"Immigrants in that era could save because the rapidly expanding American economy presented white Americans, native-born and immigrant alike, with opportunities for economic advancement that are difficult to imagine today," Anbinder, a Professor of History at the George Washington University, said.

The professor has written extensively on Irish history. His most recent book, Five Points, traced the history of nineteenth-century America's most infamous immigrant slum, focusing in particular on tenement life, inter-ethnic relations, and ethnic politics.

He relayed an account of an interview with an Irish immigrant at the time who wrote home saying he was able to afford meat twice a week. When asked if he meant twice a day the emigrant said no one at home would ever believe that level of prosperity.